package org.zuel.huhuForum.util;


import org.apache.commons.codec.binary.Base64;
import org.apache.commons.io.IOUtils;
import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import  java.util.HashMap;
import java.util.Map;


public class PasswdUtil {

    public static final String CHARSET = "UTF-8";
    public static final String RSA_ALGORITHM = "RSA";
    private static final String PRIVATE_KEY="MIIBUwIBADANBgkqhkiG9w0BAQEFAASCAT0wggE5AgEAAkEAtbbqyBmP2aLm4TO53N-pEOtYcOPg9x9vV1LNdJZ9DWxZi3jG9xtdB8SIH0Mt"+
            "_aI2xakojmzaL8AE2gAEn9udVQIDAQABAkBnSHqWFYFf0GmuYvongrDTvxDbyYpaq"+
            "_FbDuNcexTFBXNAfHhq7y9h3NBTqdFKTHZgYXlYjZWcBphEmhf4w"+
            "_ABAiEA9zIoRTWh8xjt2tONyTn04UIPESKNL0WrFsTmn9u2pgECIQC8L7lf7vkMIU8KUYIJLkxp5F4VNVBD6YtXQ7EwZ9x"+
            "_VQIgNNMmIewdKKr6IVo2IXteJkkMmTfN_f0gW6RGOIEmXgECIHm7fXTbR2tbWJ_"+
            "aHf4GXxPY0Ctz81obBzIJ7eLcLLyJAiBkHYzDsh8Uq98ubPhgnDFeTKfpmfZUjmfq53OndSde-Q";
    private static final String PUBLIC_KEY="MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBALW26sgZj9mi5uEzudzfqRDrWHDj4Pcfb1dSzXSWfQ1sWYt4xvcbXQfEiB9DLf2iNsWpKI5s2i_ABNoABJ_bnVUCAwEAAQ";

    public static Map<String, String> createKeys(int keySize ) {
        //为RSA算法创建一个KeyPairGenerator对象（KeyPairGenerator，密钥对生成器，用于生成公钥和私钥对）
        KeyPairGenerator kpg;
        try {
            kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM);
        } catch (NoSuchAlgorithmException e) {
            throw new IllegalArgumentException("No such algorithm-->[" + RSA_ALGORITHM + "]");
        }
        //初始化KeyPairGenerator对象,密钥长度
        kpg.initialize(keySize);
        //生成密匙对
        KeyPair keyPair = kpg.generateKeyPair();
        //得到公钥
        Key publicKey = keyPair.getPublic();
        //返回一个publicKey经过二次加密后的字符串
        String publicKeyStr = Base64.encodeBase64URLSafeString(publicKey.getEncoded());
        //得到私钥
        Key privateKey = keyPair.getPrivate();
        //返回一个privateKey经过二次加密后的字符串
        String privateKeyStr = Base64.encodeBase64URLSafeString(privateKey.getEncoded());

        Map<String, String> keyPairMap = new HashMap<String, String>();
        keyPairMap.put("publicKey", publicKeyStr);
        keyPairMap.put("privateKey", privateKeyStr);
        return keyPairMap;
    }
    /**
     * 得到公钥
     * @param publicKey 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPublicKey getPublicKey(String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        //通过X509编码的Key指令获得公钥对象</span>
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey));
        RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);
        return key;
    }
    /**
     * 得到私钥
     * @paramprivateKey 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPrivateKey getPrivateKey() throws InvalidKeySpecException, NoSuchAlgorithmException {
        //通过PKCS#8编码的Key指令获得私钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(PRIVATE_KEY));
        RSAPrivateKey key = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);
        return key;
    }
    /**
     * 公钥加密
     * @param data
     * @param publicKey
     * @return
     */
        public static  String  publicEncrypt (String data, RSAPublicKey publicKey) {
            try {
                Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
                cipher.init(Cipher.ENCRYPT_MODE, publicKey);
                return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));
            } catch (NoSuchPaddingException e) {
                e.printStackTrace();
            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
            } catch (InvalidKeyException e) {
                e.printStackTrace();
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
            return null;
        }
    /**
     * 私钥解密
     * @param data
     * @return
     */
     public static  String  privateDecrypt (String data) throws InvalidKeySpecException, NoSuchAlgorithmException {
         RSAPrivateKey privateKey=getPrivateKey();
         try {
             Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
             cipher.init(Cipher.DECRYPT_MODE, privateKey);
             return new  String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), privateKey.getModulus().bitLength()), CHARSET);
         } catch (NoSuchPaddingException e) {
             e.printStackTrace();
         } catch (NoSuchAlgorithmException e) {
             e.printStackTrace();
         } catch (InvalidKeyException e) {
             e.printStackTrace();
         } catch (UnsupportedEncodingException e) {
             e.printStackTrace();
         }
         return null;
     }

    /**
     * 私钥加密
     * @param data
     * @param privateKey
     * @return
     */
     public  static  String  privateEncrypt (String data, RSAPrivateKey privateKey){
         try{
             Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
             cipher.init(Cipher.ENCRYPT_MODE, privateKey);
             return  Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), privateKey.getModulus().bitLength()));

         } catch (NoSuchPaddingException e) {
             e.printStackTrace();
         } catch (UnsupportedEncodingException e) {
             e.printStackTrace();
         } catch (NoSuchAlgorithmException e) {
             e.printStackTrace();
         } catch (InvalidKeyException e) {
             e.printStackTrace();
         }
         return null;
     }
    /**
     * 公钥解密
     * @param data
     * @param publicKey
     * @return
     */
     public static  String  publicDecrypt (String data, RSAPublicKey publicKey) {
         try{
             Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
             cipher.init(Cipher.DECRYPT_MODE, publicKey);
             return new  String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);

         } catch (NoSuchPaddingException e) {
             e.printStackTrace();
         } catch (NoSuchAlgorithmException e) {
             e.printStackTrace();
         } catch (InvalidKeyException e) {
             e.printStackTrace();
         } catch (UnsupportedEncodingException e) {
             e.printStackTrace();
         }
         return null;
     }

      private static byte[] rsaSplitCodec(Cipher cipher,  int  opmode,  byte[] datas, int  keySize){
         int maxBlock = 0 ;
         if (opmode == Cipher.DECRYPT_MODE){
            maxBlock = keySize /  8 ;
        } else {
                maxBlock = keySize /  8  -  11 ;
        }
        ByteArrayOutputStream out =  new  ByteArrayOutputStream();
         int  offSet =  0 ;
         byte[] buff;
         int  i = 0;
        try{
                while(datas.length > offSet){
                if(datas.length-offSet > maxBlock){
                buff = cipher.doFinal(datas, offSet, maxBlock);
            }else{
                    buff = cipher.doFinal(datas, offSet, datas.length-offSet);
                }
            out.write(buff, 0, buff.length);
            i++;
            offSet = i * maxBlock;
        }
        }catch(Exception e){
           throw new RuntimeException("私钥解密时出现异常,加解密阀值为["+maxBlock+"]的数据时发生异常", e);
        }
        byte[] resultDatas = out.toByteArray();
        IOUtils.closeQuietly(out);
       return  resultDatas;
    }

    public static void main(String[] args) throws InvalidKeySpecException, NoSuchAlgorithmException {
        RSAPublicKey key=getPublicKey(PUBLIC_KEY);
        String a=publicEncrypt("123456",key);
        String md5NewPassword = CommunityUtil.md5("123456");
        System.out.println(md5NewPassword);
    }




}